A vacuum cleaner generally uses an air pump to create a partial vacuum for lifting dust and dirt, usually from floors, and optionally from other surfaces as well. The vacuum cleaner typically collects dirt either in a dust bag or a cyclone for later disposal. Vacuum cleaners, which are used in homes as well as in industry, exist in a variety of sizes and models, such as small battery-operated hand-held devices, domestic central vacuum cleaners, huge stationary industrial appliances that can handle several hundred liters of dust before being emptied, and self-propelled vacuum trucks for recovery of large spills or removal of contaminated soil. These robots have a drive assembly that provides a motive force to autonomously move the cleaning device along a cleaning path.
Autonomous robotic vacuum cleaners generally navigate, under normal operating conditions, a floor surface of a living space while vacuuming the floor. Autonomous robotic vacuum cleaners generally include sensors that allow it to avoid obstacles, such as walls, furniture, or stairs. The robotic vacuum cleaner may alter its drive direction (e.g., turn or back-up) when it bumps into an obstacle. The robotic vacuum cleaner may also alter drive direction or driving pattern upon detecting exceptionally dirty spots on the floor.
Other types of tasks are also performed by robots autonomously navigated across floors and through rooms containing various objects.
Various types of sensing systems have been employed to detect obstacles while the robot is being propelled across a floor. Objects such a robot may encounter include chair and table legs that may be wide or narrow, dark or light.